Navien Tankless Water Heater Comments and questions

I am considering getting a navien tankless water heater. Originally I decided against tankless because of the maintenance issue but these naviens claim that they don't require any maintenance. My plumber is the one that told me about them. They also can be vented with pvc instead of stainless. Pretty neat. Anybody heard of them or has used them. Thanks

Here's an unheard of brand from Korea that is promising a tankless heater that needs no maintenance. Wow! Where do I sign up? Don't kid yourself, everything manufactured will need some kind of maintenance or repair.

Here is a recent article from Consumer Reports posted a few weeks ago by another forum user. I suggest you read it carefully.

Heating water accounts for up to 30 percent of the average home's energy budget. Some makers of gas-fired tankless water heaters claim their products can cut your energy costs up to half over regular storage heaters. So is it time to switch?

Probably not. Gas tankless water heaters, which use high-powered burners to quickly heat water as it runs through a heat exchanger, were 22 percent more energy efficient on average than the gas-fired storage-tank models in our tests. That translates into a savings of around $70 to $80 per year, based on 2008 national energy costs. But because they cost much more than storage water heaters, it can take up to 22 years to break evenâ€”longer than the 20-year life of many models. Moreover, our online poll of 1,200 readers revealed wide variations in installation costs, energy savings, and satisfaction.

With the help of an outside lab, we pitted Takagi and Noritz gas-fired tankless water heaters against three storage water heaters. EvenWe didn't test electric tankless heaters because many can't deliver hot water fast enough to replace a conventional water heater if ground*water is cold. in areas with warm groundwater, most homeowners would need to upgrade their electrical service to power a whole-house tankless model.

Our tests simulated daily use of 76 to 78 gallons of hot water. That's the equivalent of taking three showers, washing one laun*dry load, running the dishwasher once (six cycles), and turning on the faucet nine times, for a total of 19 draws. While that's considered heavy use compared with the standard Department of Energy test, we think it more accurately represents an average family's habits. We also ran more than 45,000 gallons of very hard water through a tanked model and a Rinnai tankless model to simulate about 11 years of regular use.

Here's what else we found:

Water runs hot and cold
Manufacturers of tankless water heaters are fond of touting their products' ability to provide an endless amount of hot water. But inconsistent water temperatures were a common complaint among our poll respondents. When you turn on the faucet, tankless models feed in some cold water to gauge how big a temperature rise is needed. If there's cool water lingering in your pipes, you'll receive a momentary "cold-water sandwich" between the old and new hot water. And a tankless water heater's burner might not ignite when you try to get just a trickle of hot water for, say, shaving.

Nor do tankless water heaters deliver hot water instantaneously. It takes time to heat the water to the target temperature, and just like storage water heaters, any cold water in the pipes needs to be pushed out. And tankless models' electric controls mean you'll also lose hot water during a power outage.

Up-front costs are high
The tankless water heaters we tested cost $800 to $1,150, compared with $300 to $480 for the regular storage-tank types. Tankless models need electrical outlets for their fan and electronics, upgraded gas pipes, and a new ventilation system. That can bring average installation costs to $1,200, compared with $300 for storage-tank models.

Tankless units might need more care
During our long-term testing, an indicator on the tankless model warned of scale buildup. We paid $334 for special valves and a plumber to flush out the water heater with vinegar. Many industry pros recommend that tankless models be serviced once a year by a qualified technician. Calcium buildup can decrease efficiency, restrict water flow, and damage tankless models. Experts suggest installing a water softener if your water hardness is above 11 grains per gallon. Ignoring this advice can shorten your warranty.

Efficient storage models are pricey
We also tested the $1,400 Vertex, a high-efficiency storage water heater by A.O. Smith. The manufacturer claims its installation costs are similar to a regular storage model. But its high cost offsets much of the roughly $70 per year the Vertex will save you. Instead, we recommend buying a conventional storage water heater with a 9- or 12-year warranty. In previous tests, we found that those models generally had thicker insulation, bigger burners or larger heating elements, and better corrosion-fighting metal rods called anodes.

There's something to that- it'll be awhile before NavienAmerica is put to the full service test. But the designers & manufacturers behind it aren't 3rd rate slouches.

Scuttlebutt has it that the engineering resources behind the design are former Takagi (a top-end Japanese tankless manufacturer) guys working for the well estabished Korean boiler manufacturer. The condensing design is relatively new, but they're way up there on the true-efficiency end compared to standard non-condensing versions from other manufacturers. Whether the support & service aspects are up to snuff compared to Takagi, Rinnai or Bosch et al remains to be seen. I personally know one person using it as a combination hydronic boiler/HW backup heater for his solar heating system- no problems noted, but it's been in service less than a year. We'll see.

But no maintenance? (Wanna buy a bridge? ;-) ) Cleaning the filters is important, and if you have hard water there can be scaling issues cutting into efficiency with any tankless. But even a scaled-up Navien will be more efficient than any tank except the very-top-of-the-line European stratified-condensing tank heaters (which cost significantly more.)

BTW: That Consumer Union report/article comparing tanks to on-demands is a garbage measurement with even worse advice. See my detailed response on this thread:

Gas-fired tanks only achieve their paltry efficiency in very high-volume use profiles, and fall off an efficiency cliff the lower you go. Any tankless, even in worst-case use scenarios will beat best-case use profiles for standard tanks (even beating some more sophisticated expensive condensing tanks!) Tankless HW heaters have their quirks, but they're know, with known measures for mitigating them.

But if your space heating is done with pumped hot water you'll usually get better overall performance at a much lower up-front cost (without the quirks) by adding an indirect-fired HW tank as a priority zone onto the existing heating system. The added value gas saved by the Navien's condensing aspect won't likely be greater than the boost you get to the overall system efficiency by increasing the duty cycle of the heating system boiler- even a lowly 83% AFUE cast-iron boiler.

It is all true. Best system we have worked with. Not only do you get stainless steel heat exchangers but Dual heat exchangers with condensing technology.
The system is 16-20% more efficient than any other regular tankless in the industry.

It is all true. Best system we have worked with. Not only do you get stainless steel heat exchangers but Dual heat exchangers with condensing technology.
The system is 16-20% more efficient than any other regular tankless in the industry.

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Yadda yadda...

What is your total installed base?

How many of them are being used in combi-systems? (And what percentage is HW only?)

What's the average length of service in your installed base? (And how often have you been called back for service, adjusment or repair?)

They may be the greatest tankless ever, but near as I can tell it's still the thin edge of the market-penetration edge. Real reliablity numbers will show up after there are significant numbers in service for a decade or more (unless there are real lemon-issues.) For the time being I'm agnostic on 'em.

And I've yet to see anything that looked like real test data on their condensing efficiency in combi systems. (I'd be surprised if the combustion efficiency was any more than 86-88% when running fan coils or maintaining heating buffer tanks, a meagre premium over a standard Takagi or Rinnai in those applications.)

Are you a plumber, environmentalist, etc? Our base is a solid firm number. Both systems are being used through out the US right now. Our units have been installed in the last 12 months with no call backs or problems what so ever. But if we do get call back, so what! We go, diagnose and find the solution.

Just like any equipment from plasma TV's to Hot water heaters. Its not always going to be perfect, maintenance free.

Navien HWH have over 10 years of field testing DATA.

The CEO of Navien now, used to be the VP of TAKAGI... and Takagi is the worlds oldest leading tankless manufacture in the world.

To me- Rinnai, Takagi, Rheem, Navien, Bosch are all wonderful tankless units that require maintenance and servicing at least once every two years.

No matter what they say- You can't get a unit HWH installed and walk away forever and not look back to check on it!

How many of them are being used in combi-systems? (And what percentage is HW only?)

What's the average length of service in your installed base? (And how often have you been called back for service, adjusment or repair?)

They may be the greatest tankless ever, but near as I can tell it's still the thin edge of the market-penetration edge. Real reliablity numbers will show up after there are significant numbers in service for a decade or more (unless there are real lemon-issues.) For the time being I'm agnostic on 'em.

And I've yet to see anything that looked like real test data on their condensing efficiency in combi systems. (I'd be surprised if the combustion efficiency was any more than 86-88% when running fan coils or maintaining heating buffer tanks, a meagre premium over a standard Takagi or Rinnai in those applications.)

Maybe it needs to be said.... Internet opinions are not a true indications of the state of the technology. When you have kids, the unhappy ones are noisy, whiny, complaining... and BLOGGING about it! The happy kids you don't usually hear from and as such may not hear how good it is. I would imagine that complainers of tankless systems on the internet are a very small percentage of the installed base... ie: happy users far outnumber the unhappy users. Possible exception, Bosch users!

Some people, a growing number I might add, don't care about "the numbers". They install them for other reasons, I know I did. Not to worry, the next generation of plumbers will probably embrace technological change readily.

What other reasons? This is a crap statement. I like to spend more money for very little return because what? Give me a break. And don't go telling me they are environmentally friendly because that's crap also. They are manufactured in a factory spewing carbon into the air. They burn gas spewing carbon into the air. So what are the "other reasons" Your house is so cramped you cant take up another 6 cubic feet of space? face it. You got talked into it, bought it and now have to find a way to justify it. So where is the advantage? Oh I know. It doesn't run all day long when I'm not home (that one from Trethewey) News for you guys a newer tank type heater doesn't run either due to the very high level of insulation. In fact last winter I shut off my boiler. Went to Florida for a week. Came home and the tank was still hot (Buderus indirect) You all have been sold a load of crap just like Hybrid cars, wind mills and all that other junk that costs 3 times more than it will EVER pay back and has zero environmental impact. If this junk did what it was supposed to do, why would the government have to subsidise it?

Don't forget to watch the biggest scam of all on Tuesday.

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What a crock of bull NHMaster! I didn't get talked into installing a tankless water heater by anyone. No plumber came to my house and gave me an outlandish quote for some inferior technology that he felt comfortable installing because he doesn't want to look at the future and see it about to run over him like a mile long freight train. I made an educated purchase based on my own research... period. I will live with it just fine.

Frankly, NHMaster, your refusal to see anyone elses point of view on this subject and quickly take swipes when posters don't walk lock step with you is very disturbing. I'm sure you won't lose too much sleep giving highly slanted, old world views. Maybe an ignore is best in this situation.

What a crock of bull NHMaster! I didn't get talked into installing a tankless water heater by anyone. No plumber came to my house and gave me an outlandish quote for some inferior technology that he felt comfortable installing because he doesn't want to look at the future and see it about to run over him like a mile long freight train. I made an educated purchase based on my own research... period. I will live with it just fine.

Frankly, NHMaster, your refusal to see anyone elses point of view on this subject and quickly take swipes when posters don't walk lock step with you is very disturbing. I'm sure you won't lose too much sleep giving highly slanted, old world views. Maybe an ignore is best in this situation.

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The Future? If you really had done the research you would have discovered that tankless, instantaneous water heaters have been around for better than 30 years now. You would also have discovered that the operational cost versus the cost of the equipment and installation just don't add up. I have listened too and done a whole lot of research on the subject, check my bio, it's my job. I have absolutly no stake or interest in what your decision is or was. I only point out the facts. That you choose to ignoer themis naturally, your own business. before I bid you adieu though, please inform us as to the "other reasons" for installing your tankless heater.

please inform us as to the "other reasons" for installing your tankless heater.

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You have been told in several other posts by myself why I went with one. Go look them up since you obviously have ignored them in the past. I have good reasons to use tankless in my situation and will continue to pass the good word in light of the whirlwind of bad press by a few here.

sorry, I didn't catch that part. But going through your pas posts I really couldn't find a compelling reason other than the great price you got on the unit. That is in itself reason for question since even with my discount I can't buy one for that. Aside from that though, How far did you have to run the stainless steel vent pipe up through the roof because that stuff ain't cheap either. Oh and while we are at it, did you check the maximum allowable length of the vertical vent pipe. Because those darned things can and will condensate on long runs, especially if the pipe passes through a cold attic. probably nothing to worry about though.

Maybe it seems like I and others are dissing you or having sport with you and nothing could be further from the truth. What we are trying do do is educate a public that has been hypnotized into buying this line of efficiency and economy that just flat does not exist. The math is the math. People lie. Numbers do not. So other than the one in a lifetime price you got on the unit, and your ability to self install it (and btw I looked at your pictures and you did a nice job there) why would anyone consider installing one of these. Please don't give us the line about a tank type running all day long when you are not hoem because they don't. If they did the operational cost differential would be much greater than it is, and that runs about 4% normally. 4% projected over 10 or 20 years does not make up for the cost and service.

What other reasons? This is a crap statement. I like to spend more money for very little return because what? Give me a break. And don't go telling me they are environmentally friendly because that's crap also. They are manufactured in a factory spewing carbon into the air. They burn gas spewing carbon into the air. So what are the "other reasons" Your house is so cramped you cant take up another 6 cubic feet of space? face it. You got talked into it, bought it and now have to find a way to justify it. So where is the advantage? Oh I know. It doesn't run all day long when I'm not home (that one from Trethewey) News for you guys a newer tank type heater doesn't run either due to the very high level of insulation. In fact last winter I shut off my boiler. Went to Florida for a week. Came home and the tank was still hot (Buderus indirect) You all have been sold a load of crap just like Hybrid cars, wind mills and all that other junk that costs 3 times more than it will EVER pay back and has zero environmental impact. If this junk did what it was supposed to do, why would the government have to subsidise it?

Don't forget to watch the biggest scam of all on Tuesday.

Click to expand...

What would it cost to have a Boderus indirect installed in the home of a consumer? Include the cost of the indirect water tank, required pipes, additional accessories, sales tax, markup, delivery, warranty!

You also need to have a boiler (AKA water heater). How much does that add to cost installed as a complete system including venting and all labor and accessories?

It doesn't run all day long when I'm not home (that one from Trethewey) News for you guys a newer tank type heater doesn't run either due to the very high level of insulation. In fact last winter I shut off my boiler. Went to Florida for a week. Came home and the tank was still hot (Buderus indirect)

The boiler has the re-set controller on it. Alows me to shut off the hot water call.

An indirect will cost slightly less than a tankless, never run out of hot water and operate at a much lower cost. However it's only an option if you have a boiler. If not stick with a tank type water heater. There are lot's of comparison charts out there for the various ways to make hot water. It's only a Google away.

An indirect will cost slightly less than a tankless, never run out of hot water and operate at a much lower cost. However it's only an option if you have a boiler. If not stick with a tank type water heater.

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You also don't need to have an indirect tank, a tankless water heater, or a tank type water heater if you have a boiler. The boilers that I am familiar with (limited) are in effect tankless water heaters that have a small heated tank located inside the unit.

A couple of thousand for an indirect tank could be considered to be a waste of money.

By the way, I have nothing against a standard tank type water heater. I needed the floor space, so I used a tankless. I now have a direct vent gas fireplace taking up part of the floor space where that old water heater was located. I needed to heat my home theater room that I located in the basement, and the gas fireplace was a nice way to provide heat for that zone. The gas fireplace also keeps me away from problems caused by HVAC contractors!

You also don't need to have an indirect tank, a tankless water heater, or a tank type water heater if you have a boiler. The boilers that I am familiar with (limited) are in effect tankless water heaters that have a small heated tank located inside the unit.
A couple of thousand for an indirect tank could be considered to be a waste of money.

By the way, I have nothing against a standard tank type water heater. I needed the floor space, so I used a tankless. I now have a direct vent gas fireplace taking up part of the floor space where that old water heater was located. I needed to heat my home theater room that I located in the basement, and the gas fireplace was a nice way to provide heat for that zone. The gas fireplace also keeps me away from problems caused by HVAC contractors!

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The tankless coil is very very inefficient as it requires the boiler to maintain at least 160 degrees year round.

sorry, I didn't catch that part. But going through your pas posts I really couldn't find a compelling reason other than the great price you got on the unit. That is in itself reason for question since even with my discount I can't buy one for that. Aside from that though, How far did you have to run the stainless steel vent pipe up through the roof because that stuff ain't cheap either. Oh and while we are at it, did you check the maximum allowable length of the vertical vent pipe. Because those darned things can and will condensate on long runs, especially if the pipe passes through a cold attic. probably nothing to worry about though.

Maybe it seems like I and others are dissing you or having sport with you and nothing could be further from the truth. What we are trying do do is educate a public that has been hypnotized into buying this line of efficiency and economy that just flat does not exist. The math is the math. People lie. Numbers do not. So other than the one in a lifetime price you got on the unit, and your ability to self install it (and btw I looked at your pictures and you did a nice job there) why would anyone consider installing one of these. Please don't give us the line about a tank type running all day long when you are not hoem because they don't. If they did the operational cost differential would be much greater than it is, and that runs about 4% normally. 4% projected over 10 or 20 years does not make up for the cost and service.

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Educating the public is fine and I commend you for taking time to do so. But keep in mind, what does not work in New England may work just fine south of the Mason-Dixon line (ie, Texas). Condensation of the exhaust flue, low inlet water temp, large demand, etc all must be taken into account before recommending a hot water system. Some quality tankless systems take this and other issues into account. Rinnia for example has a kit for collecting flue condensation when the vertical run is more than 6 feet or so. My vertical run was less than 5 feet and no issue. Limited floor space for more than one waterheater and a family of 6 is what caused me to consider a "quality" tankless water heater. The $5 per month savings on my gas bill was not the reason as I NEVER looked at getting my money back on the system.

One other note, I really liked the vent system for the Rinnia. It is an outer 5.5" pvc pipe for combustion air intake with an inner 3" steel exhaust flue. Easy to cut and work with. Cost more than "B" vent but possibly more long lasting and doesn't take combustion air from garage in my case

BTW, My boys and I made the pilgrimage to Mecca and saw the Red Sox play last year at Fenway!

Educating the public is fine and I commend you for taking time to do so. But keep in mind, what does not work in New England may work just fine south of the Mason-Dixon line (ie, Texas). Condensation of the exhaust flue, low inlet water temp, large demand, etc all must be taken into account before recommending a hot water system.

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I live in MA, and a tankless works fine in my single family home here even with water coming in at 40 degrees. Just stay within the flow rate of the heater and you will never have the problem of running out of hot water.

If you "need" to run three shower heads at the same time when you shower (AKA large demand), then a tankless is probably not a good idea anywhere.

I am not sure if the electric version of a whole house tankless is a good idea. From what I have read, some utilities prohibit their use due to excessive short term demands on the power grid.